NEW YORK (Reuters) - U.S.
stock index futures were little changed on Tuesday, with
investors finding few reasons to buy after a rally in
the previous session that took the S&P 500 above 2,000
for the first time.

The S&P failed to hold that level on Monday, though the benchmark
index ended at a new closing high. Equities have rallied lately,
with both the Dow and S&P advancing in seven of the last 10
sessions, while the Nasdaq has climbed in eight of the last 10
trading days.

That momentum is still considered intact, and the S&P's
price-to-earnings ratio is within historical norms, leading many
analysts to believe the market is not overvalued. Nonetheless,
further gains may be a challenge without positive catalysts and amid
potential headwinds such as a reduction in Federal Reserve stimulus
and a simmering conflict between Ukraine and Russia.

Much of the market's recent gains have come on low volume,
suggesting many traders may be reluctant to jump in at current
levels.

Biotechnology stocks were among the biggest drivers during Monday's
rally. That appeared to continue Tuesday, with Achillion
Pharmaceuticals <ACHN.O> up 6.1 percent to $11.44 before the opening
bell. Gilead Sciences Inc rose 0.6 percent to $108.13.

Shares of Best Buy Co Inc fell 4.7 percent to $30.50 in
premarket trading after the electronics retailer reported lower
second-quarter revenue and forecast a drop in same-store sales in
the second half of the year.

Digital Ally Inc jumped 6.4 percent to $13.30 in premarket trading,
extending a recent surge that has seen shares of the wearable camera
maker more than triple this month alone. The recent fatal police
shooting of an unarmed black teenager in Missouri has fueled
interest in the company's devices. The stock was the Nasdaq's
heaviest premarket mover.

Amazon.com Inc late Monday agreed to buy the live-streaming gaming
network Twitch Interactive for about $970 million in cash.